Resonating Valence Bond Theory of Superconductivity for Dopant Carriers: Application to the Cobaltates

TL;DR

This paper develops a resonating valence bond (RVB) mean field theory for dopant carriers within the $t$--$J$ model and applies it to cobaltates, successfully reproducing the experimental phase diagram of superconductivity.

Contribution

It introduces a dopant-based RVB mean field approach within the $t$--$J$ model and applies it to cobaltates, providing a theoretical framework for their superconductivity.

Findings

Phase diagram $T_c$ versus doping matches experiments qualitatively

RVB theory captures key features of cobaltate superconductivity

The approach offers insights into dopant-driven superconductivity mechanisms

Abstract

Within the $t$--$J$ model Hamiltonian we present a RVB mean field theory directly in terms of dopant particles. We apply this theory to $\mathrm{Na}_{x}\mathrm{CoO_{2}}\cdot y% \mathrm{H_{2}0}$ and show that the resulting phase diagram $T_c$ versus doping is in qualitative agreement with the experimental results.